Publications

Order by: publication date number of citations

• Probing pair correlations in Fermi gases with Ramsey-Bragg interferometry

  Théo Malas-Danzé, Alexandre Dugelay, Nir Navon, Hadrien Kurkjian

  SciPost Phys. 17, 024 (2024) · published 29 July 2024 | Toggle abstract · pdf

  We propose an interferometric method to probe pair correlations in a gas of spin-$1/2$ fermions. The method consists of a Ramsey sequence where both spin states of the Fermi gas are set in a superposition of a state at rest and a state with a large recoil velocity. The two-body density matrix is extracted via the fluctuations of the transferred fraction to the recoiled state. In the pair-condensed phase, the off-diagonal long-range order is directly reflected in the asymptotic behavior of the interferometric signal for long interrogation times. The method also allows to probe the spatial structure of the condensed pairs: the interferometric signal is an oscillating function of the interrogation time in the Bardeen-Cooper-Schrieffer regime; it becomes an overdamped function in the molecular Bose-Einstein condensate regime.

  1 citation

• Measurement of Transverse Spin Dependent Azimuthal Correlations of Charged Pion(s) in $p^{\uparrow} p$ Collisions at $\sqrt s = 200$ GeV at STAR

  Babu R. Pokhrel

  SciPost Phys. Proc. 8, 047 (2022) · published 12 July 2022 | Toggle abstract · pdf

  At the leading twist, the transversity distribution function, $h^{q}_{1}(x)$, where $x$ is the longitudinal momentum fraction of the proton carried by quark $q$, encodes the transverse spin structure of the nucleon. Extraction of it is difficult because of its chiral-odd nature. In transversely polarized proton-proton collisions ($p^\uparrow p$), $h_{1}^{q}(x)$ can be coupled with another chiral-odd partner, a spin-dependent fragmentation function (FF). The resulting asymmetries in hadron(s) azimuthal correlations directly probe $h_{1}^{q}(x)$. We report the measurement of correlation asymmetries for charged pion(s) in $p^\uparrow p$, through the Collins and the Interference FF channel.

  1 citation

• First measurement results from DANAE - Demonstrating DePFET RNDR on a prototype Matrix

  Alexander Bähr, Holger Kluck, Peter Lechner, Jelena Ninkovic, Jochen Schiek, Hexi Shi, Wolfgang Treberspurg, Johannes Treis

  SciPost Phys. Proc. 12, 066 (2023) · published 5 July 2023 | Toggle abstract · pdf

  In the search for dark matter particle candidates, the mass region below 1 GeV/c$^2$ is relatively unprobed. Utilizing a low-noise silicon sensor as a sensitive target material, we aim to study the event signature of recoils between dark matter candidates and bound electrons. As the deposited energy is only a few eV, a sensor capable of detecting these low signals is required. We present first measurements on a prototype pixel matrix. It is based on the RNDR DePFET principle and provides a deep sub-electron readout noise of 0.2e$^-$ and below.

  1 citation

• NLO inclusive $J/ψ$ photoproduction at large $P_T$ at HERA and the EIC

  Carlo Flore, Jean-Philippe Lansberg, Hua-Sheng Shao, Yelyzaveta Yedelkina

  SciPost Phys. Proc. 8, 011 (2022) · published 11 July 2022 | Toggle abstract · pdf

  We study inclusive $J/\psi$ photoproduction at NLO at large $P_T$ at HERA and the EIC. Our computation includes NLO QCD leading-$P_T$ corrections, QED contributions via an off-shell photon as well as those from $J/\psi$+charm channels. For the latter, we employ the variable-flavour-number scheme. Our results are found to agree with the latest HERA data by H1 and provide, for the first time, a reliable estimate of the EIC reach for such a measurement. Finally, we demonstrate the observability of $J/\psi$+charm production and the sensitivy to probe the non-perturbative charm content of the proton at high $x$, also known as intrinsic charm, at the EIC.

  1 citation

• Codebase release 0.5 for HarmonicBalance.jl

  Jan Košata, Javier del Pino, Toni L. Heugel, Oded Zilberberg

  SciPost Phys. Codebases 6-r0.5 (2022) · published 24 August 2022 | Toggle abstract · src

  HarmonicBalance.jl is a publicly available Julia package designed to simplify and solve systems of periodic time-dependent nonlinear ordinary differential equations. Time dependence of the system parameters is treated with the harmonic balance method, which approximates the system's behaviour as a set of harmonic terms with slowly-varying amplitudes. Under this approximation, the set of all possible steady-state responses follows from the solution of a polynomial system. In HarmonicBalance.jl, we combine harmonic balance with contemporary implementations of symbolic algebra and the homotopy continuation method to numerically determine all steady-state solutions and their associated fluctuation dynamics. For the exploration of involved steady-state topologies, we provide a simple graphical user interface, allowing for arbitrary solution observables and phase diagrams. HarmonicBalance.jl is a free software available at https://github.com/NonlinearOscillations/HarmonicBalance.jl.

  1 citation

• Proton penetration efficiency over a high altitude observatory in Mexico

  S. Miyake, T. Koi, Y. Muraki, Y. Matsubara, S. Masuda, P. Miranda, T. Naito, E. Ortiz, A. Oshima, T. Sakai, T. Sako, S. Shibata, H. Takamaru, M. Tokumaru, J. F. Valdés-Galicia

  SciPost Phys. Proc. 13, 001 (2023) · published 28 September 2023 | Toggle abstract · pdf

  In association with a large solar flare on November 7, 2004, the solar neutron detectors located at Mt. Chacaltaya (5,250 m) in Bolivia and Mt. Sierra Negra (4,600 m) in Mexico recorded very interesting events. In order to explain these events, we have performed a calculation solving the equation of motion of anti-protons inside the magnetosphere. Based on these results, the Mt. Chacaltaya event may be explained by the detection of solar neutrons, while the Mt. Sierra Negra event may be explained by the first detection of very high energy solar neutron decay protons (SNDPs) around 6 GeV.

  1 citation

• TMD observables in unpolarised Semi-Inclusive DIS at COMPASS

  Andrea Moretti

  SciPost Phys. Proc. 8, 144 (2022) · published 14 July 2022 | Toggle abstract · pdf

  In 2016 and 2017, the COMPASS Collaboration at CERN collected a large sample of DIS events with a longitudinally polarised 160 GeV/$c$ muon beam scattering off a liquid hydrogen target. Part of the collected data has been analysed to extract preliminary results for the amplitudes of the modulations in the azimuthal angle of the charged hadrons and for their transverse-momentum distributions. These observables give relevant information for the study of the transverse momentum and spin structure of the nucleon. Similarly to the results obtained in COMPASS with a deuteron target, the azimuthal asymmetries exhibit interesting kinematic dependences, while the squared-transverse-momentum distributions can be described by two exponentials.

  1 citation

• Algebraic Bethe Ansatz for spinor R-matrices

  Vidas Regelskis

  SciPost Phys. 12, 067 (2022) · published 17 February 2022 | Toggle abstract · pdf

  We present a supermatrix realisation of $q$-deformed spinor-spinor and spinor-vector $R$-matrices. These $R$-matrices are then used to construct transfer matrices for $U_{q^2}(\mathfrak{so}_{2n+1})$- and $U_{q}(\mathfrak{so}_{2n+2})$-symmetric closed spin chains. Their eigenvectors and eigenvalues are computed.

  1 citation

• An infalling observer and behind the horizon cutoff

  Amin Akhavan, Mohsen Alishahiha

  SciPost Phys. 7, 073 (2019) · published 3 December 2019 | Toggle abstract · pdf

  Using Papadodimas and Raju construction of operators describing the interior of a black hole, we present a general relation between partition functions of operators describing inside and outside the black hole horizon. In particular for an eternal black hole the partition function of the interior modes may be given in terms those partition functions associated with the modes of left and right exteriors. By making use of this relation we observe that setting a finite UV cutoff will enforce us to have a cutoff behind the horizon whose value is fixed by the UV cutoff. The resultant cutoff is in agreement with what obtained in the context of holographic complexity.

  1 citation

• Boundary overlap in the open XXZ spin chain

  Charbel Abetian, Nikolai Kitanine, Veronique Terras

  SciPost Phys. 18, 026 (2025) · published 21 January 2025 | Toggle abstract · pdf

  In this paper we compute the overlaps of the ground states for the open spin chains after a change of one of the boundary magnetic fields. It can be considered as the first step toward the study of the boundary quench problem: behaviour of an open spin chain after an abrupt change of one boundary magnetic field.

  1 citation